Joss Whedon, however, takes this notion to the next level.
If Whedon likes an actor, he will work with them again, and it's as simple as that. Considering how many projects Whedon has worked on (as a director, writer and producer, we should add), that has resulted in him using a lot of actors more than once.
The director has worked on television shows like Buffy the Vampire Slayer, Angel, Firefly, Dollhouse and Agents of S.H.I.E.L.D, as well as movies like Serenity, The Cabin in the Woods, The Avengers, Much Ado About Nothing and Avengers: Age of Ultron - and it might surprise you just how many of those projects have featured the same actors.
With that in mind, we're going to run through just some of the actors that Whedon has utilized the services of on more than one occasion. Here are thirty-one talented actors ("Whedonites") Whedon likes to recycle in his work.
31 Tom Lenk
Tom Lenk's most famous role to date is undoubtedly as the wannabe-supervillain-turned Scooby Gang member Watcher Andrew Wells in Buffy the Vampire Slayer and Angel (albeit briefly in the latter), but Whedon utilized him more than that.
In addition to that role, Lenk also played Cyrus - a vampire minion of Harmony Kendall - in season five of Buffy the Vampire Slayer (the episode "Real Me"), Ronald in Whedon's 2012 movie The Cabin in the Woods and Verges in his 2012 movie Much Ado About Nothing.
30 Dichen Lachman
Nepalese-born German-Australian actress Dichen Lachman has worked with Whedon on two different occasions - both of which were on his television shows.
First off, in Dollhouse, she portrayed series regular Sierra (who was known as Priya Tsetsang before having her memories wiped) and more recently, she played the inhuman mother of Skye (Daisy Johnson), known as Jiaying in Agents of S.H.I.E.L.D.
29 Sean Gunn
Sean Gunn, the actor/brother of Guardians of the Galaxy director James Gunn, has been utilized by Whedon on two occasions in one of his classic television shows. To be specific, Gunn appeared as two different characters on Angel.
Those two characters were Lucas and Mars - Lucas being a Brachen Demon who appeared in the season one episode “Hero,” and Mars being the human manager of the Palm Ridge Spa who appeared in the season one episode “She”. Both characters died in their respective episodes.
28 Jillian Morgese
Jillian Morgese is something of an anomaly on this list, as her first role under Whedon was merely as an extra in 2012's The Avengers. She portrayed a waitress in a restaurant who was fleeing in horror from the alien attack in New York, and based on her impact in the small role, Whedon described her as having "a quality which is undeniable" and cast her in a more substantial role.
That role was in Much Ado About Nothing, which was released later in the same year. She portrayed Hero, the daughter of lead character Leonato.
27 Felicia Day
Felicia Day has worked with Whedon on no less than three separate occasions, starting with her role in season seven of Buffy the Vampire Slayer, in which she portrayed Vi. Vi was a potential slayer who was transformed into an actual slayer in the final episode of the series.
However, she has also appeared in Whedon's brilliant web series Dr. Horrible's Sing-Along Blog, as series regular Penny, and as Mag in two different episodes of Dollhouse.
26 Ashley Johnson
Another actress who has worked with Whedon on three different occasions is Ashley Johnson. Her first Whedon role was in Dollhouse; she played Hayden Leeds in the pilot episode "Ghost" and then portrayed a character called Wendy (also known as Caroline after being with Caroline Farrell's personality) in the episode "Omega".
She also played the waitress Beth (though most of her scenes were cut) in 2012's The Avengers, and Margaret in Much Ado About Nothing later in the same year.
25 Leland Crooke
Leland Crooke is another actor that played two different characters in each of Whedon's two Buffyverse television shows, Buffy the Vampire Slayer and Angel.
For starters, he portrayed Buffy Summers' poetry professor, Professor Lilian, in season five's Buffy the Vampire Slayer episode "Tough Love", before more notably portraying the demonic Archduke Sebassis (a member of the powerful Circle of the Black Thorn) in four episodes of the final season of Angel.
24 Jack Conley
Like the previous entry on this list, Jack Conley is an actor that portrayed two different characters in Whedon's two Buffyverse television shows as well.
His first appearance in the Buffyverse was in Buffy the Vampire Slayer's season two episode "Phases," portraying the werewolf hunter known as Gib Cain. More famously, he played recurring demonic villain Sahjhan in seven episodes of Angel, found in both seasons three and five.
23 Reed Diamond
Reed Diamond is an actor who has worked with Whedon on three occasions, spanning the world of both television and movies.
His first collaboration with the director was in Dollhouse, playing the recurring character known as Laurence Dominic. Then, in 2012, he portrayed Don Pedro in Whedon's adaptation of Much Ado About Nothing. Finally, in the Agents of S.H.I.E.L.D. television series, he portrayed the North American HYDRA leader Werner Reinhardt, also known as Daniel Whitehall.
22 Sean Maher
Actor Sean Maher has worked with Whedon on two (well, we guess you could say three) different occasions in both television and in the movies.
First off, he appeared as main character Dr. Simon Tam in the television show Firefly - and, subsequently, its 2005 spin-off movie Serenity as the same character. More recently, though, he appeared in Whedon's 2012 movie adaptation of Much Ado About Nothing, where he played Don John, the brother of the aforementioned Reed Diamond's Don Pedro.
21 Spencer Treat Clark
Spencer Treat Clark had two brief roles in Whedon works - one in a movie and one on television.
He appeared in Whedon's Much Ado About Nothing, in which he played Borachio, a follower of the aforementioned Sean Maher's Don John. More recently, he appeared in season three of Agents of S.H.I.E.L.D., portraying Werner von Strucker, the son of the deceased villain Baron Wolfgang von Strucker."
20 Ron Glass
Ron Glass has appeared in two of Joss Whedon's television shows (Firefly and Agents of S.H.I.E.L.D.), as well as Firefly's 2005 spin-off Serenity.
In Firefly and Serenity, Glass portrayed main character Shepherd Derrial Book in thirteen of the fourteen episodes of the television show. He also played J. Streiten, MD in two episodes of Agents of S.H.I.E.L.D. (the "Pilot" episode and "The Magical Place").
19 Riki Lindhome
Riki Lindhome is an actress that had two brief roles in Whedon productions Buffy the Vampire Slayer and Much Ado About Nothing.
In Buffy the Vampire Slayer, she appeared in the season seven episode entitled "Him" as Cheryl, a student from Sunnydale High. Then, in Much Ado About Nothing, she portrayed Conrade, the lover of the aforementioned Sean Maher's Don John - a role originally meant for a male follower of Don John.
18 Enver Gjokaj
Half-Albanian actor Enver Gjokaj has appeared in two Whedon projects, including a television show and a movie.
First, Gjokaj appeared on television in Dollhouse as serious regular Victor (also known as Anthony Ceccoli), and then appeared in the 2012 movie The Avengers as a New York City police officer during the Chitauri invasion. Interestingly enough, he has also appeared as another Marvel Cinematic Universe character (though not under Whedon's directorship), as series regular Agent Daniel Sousa in Agent Carter.
17 Jonathan M. Woodward
Jonathan M. Woodward has played three different characters - all of which have something in common - in three of Whedon's television shows.
All of the characters appeared nice to begin with, but were later killed when they proved to be more sinister. First, he appeared as vampire Holden Webster in the Buffy the Vampire Slayer episode "Conversations with Dead People," followed by an appearance in the Firefly episode "The Message" as Tracey. Finally, he starred in seven episodes of Angel's final season as Knox.
16 Brian Thompson
Brian Thompson played two different villains in two consecutive seasons of Whedon's Buffy the Vampire Slayer.
In the show's first season, he played one of the first vampires to ever be seen on screen, the Order of Aurelius member and servant of the Master, Luke. Then, in the second season, he played the Judge, an ancient demon that “no weapon forged” could kill (Buffy killed him with a rocket launcher, as the "no weapon forged" rule didn't apply in modern times.)
15 Fran Kranz
Fran Kranz has collaborated with Whedon on three different occasions - two of which were in movies and once on television.
The television collaboration came first, as Kranz portrayed scientist Christopher "Topher" Brink in 27 episodes of Dollhouse. More recently, he appeared in two 2012 Whedon films as "the fool" Marty in The Cabin in the Woods, and as Claudio, a companion of Sean Maher's Don John, in Much Ado About Nothing.
14 Andy Hallett
The late Andy Hallett appeared in both of Whedon's Buffyverse television shows. Sadly, he tragically passed away in 2009 from congestive heart failure after numerous heart complications, followed a dental infection that spread through his bloodstream five years earlier.
In Buffy the Vampire Slayer, he made an uncredited appearance as a student in season four's brilliant episode "Hush," and far more notably, portrayed series regular Lorne (also known as The Host and Krevlornswath of the Deathwok Clan) in 76 episodes of Angel.
13 Amy Acker
Actress Amy Acker is categorically prolific when it comes to collaborating with Whedon on his projects. She has appeared in three of his television shows and two of his movies.
In terms of television work, she was series regular Winifred "Fred" Burkle (and subsequently Illyria when she took over Fred's body) in Angel. She was also a series regular in Dollhouse as Dr. Claire Saunders, and also portrayed Audrey Nathan ("the cellist" referenced in The Avengers movie) in the Agents of S.H.I.E.L.D. episode "The Only Light in the Darkness." In terms of movies, she has appeared in The Cabin in the Woods and Much Ado About Nothing, as characters Wendy Lin and Beatrice, respectively.
12 Gina Torres
Actress Gina Torres - who is the real-life wife of Laurence Fishburne - has starred in two of Whedon's television shows and in one of his movies.
In terms of television work, she starred as series regular Zoe Washburne in Firefly, and subsequently as the "Big Bad" of Angel's fourth season, the deity Jasmine. After that, she reprised her role as Zoe Washburne in the 2005 Firefly spin-off Serenity.
11 Camden Toy
Brilliant character actor Camden Toy often takes roles as weird creatures underneath heavy make-up or costumes. He's done it for Whedon no less than four times in two different television shows.
In Buffy the Vampire Slayer, he played one of the creepy Gentlemen in season four's "Hush," and also played two different evil characters in the same season where he was known as both the Ubervamp and Gnarl in season seven. He also played the ancient vampire known as the Prince of Lies in Angel.
10 Andy Umberger
Andy Umberger spent a large chunk of his career on stage, but he has also appeared in three of Whedon's television shows, Buffy the Vampire Slayer, Angel and Firefly.
In Angel, he portrayed the creepy Dr. Ronald Meltzer in the season one episode "I Fall to Pieces." In Buffy the Vampire Slayer, he played recurring demonic character D'Hoffryn in four episodes between season three and seven, and in the Firefly episode called "Serenity" (also the name of the spin-off movie, which he wasn't in), he played the Dortmunder Captain.
9 J. August Richards
J. August Richards has appeared in two different roles under the directorship of Whedon, and both were on television shows that took place almost ten years apart.
In the more famous role out of the two, Richards portrayed series regular Charles Gunn in Angel, who was a vampire hunter that became a member of the titular character's group. In the more recent role out of the two, he played recurring character Mike Peterson, the cyborg Deathlok in Agents of S.H.I.E.L.D., which is a role that is actually ongoing.
8 Adam Baldwin
Adam Baldwin's acting career has seen him appear in some huge films (Full Metal Jacket, Predator 2, Independence Day), but he has also appeared in two of Whedon's television shows, as well as one of his movies.
Most prominently in terms of his Whedon work, Baldwin was regular character Jayne Cobb in Firefly, but he also appeared on television in Angel as season five's recurring secondary "Big Bad" Marcus Hamilton. He also reprised his Firefly role in Serenity.
7 Summer Glau
Actress Summer Glau has appeared in three different Joss Whedon television shows and in one of his movies, too.
She portrayed the ghostly Prima Ballerina in Angel's season three episode "Waiting in the Wings," and then played regular character River Tam on Firefly. Lastly, as far as her Whedon television work goes, she played Bennett Halverson in Dollhouse. Like Baldwin, she too reprised her Firefly role in Serenity.
6 Nathan Fillion
Nathan Fillion is truly a bona fide "Whedonite." He acted under the directorship of Whedon on television, in movies and in a web series titled Dr. Horrible's Sing-Along Blog.
In terms of his television work under Whedon, he portrayed regular character Malcolm "Mal" Reynolds in Firefly, and was the secondary "Big Bad" in season five's Buffy the Vampire Slayer as the evil priest Caleb. In terms of his movie work under Whedon, he played Dogberry in 2012's Much Ado About Nothing.
Plus, in the aforementioned Dr. Horrible's Sing-Along Blog, he played the titular character's sworn enemy Captain Hammer.
5 Jeremy Renner
Jeremy Renner has become a Hollywood A-lister, but his early career was more modest, and as a result, he had a minor role in a Whedon television show. He also worked under Whedon in two movies.
In the season one episode of Angel called “Somnambulist,” Renner played Penn - a vampire sired by Angelus in 1786. Instrumental in his casting, Whedon chose Renner to play Clint Barton (also known as Hawkeye) in the Marvel Cinematic Universe, choosing him as the character for both 2012's The Avengers and 2015's Avengers: Age of Ultron.
4 Chris Hemsworth
Chris Hemsworth has worked under the directorship of Whedon solely on movie projects (three to be precise) and his biggest role to date came courtesy of his place in his first Whedon movie.
2012's The Cabin in the Woods was actually filmed in 2009, with Hemsworth playing "the athlete" Curt Vaughan. He impressed Whedon so much that the director campaigned for him to become Thor in the Marvel Cinematic Universe. Hemsworth auditioned to play the character and won the role, first portraying the Asgardian hero in the character's first solo movie, and then he went on to work with Whedon in 2012's The Avengers and 2015's Avengers: Age of Ultron.
It's safe to say Whedon got his wish.
3 Clark Gregg
The wonderful Clark Gregg has worked with Whedon in two movies and in one television series, although his initial work with Whedon was through none of Whedon's actions.
Gregg was already portraying S.H.I.E.L.D. agent Phil Coulson in the Marvel Cinematic Universe when he inadvertently worked under the director in 2012's The Avengers. As a result, Whedon cast him in his adaptation of Much Ado About Nothing later that same year, and even though he died in The Avengers, Whedon resurrected him to star in his television series Agents of S.H.I.E.L.D.
2 Alexis Denisof
He appeared as the timid Watcher-turned-bad-ass Wesley Wyndam-Pryce in both Buffy the Vampire Slayer and Angel. He then appeared in four episodes of Dollhouse as Senator Daniel Perrin. More recently, he appeared in Whedon's 2012 movies The Avengers and Much Ado About Nothing, portraying The Other and Benedick, respectively.
1 Eliza Dushku
Eliza Dushku has appeared in three television shows that have been directed by Whedon, including Buffy the Vampire Slayer, Angel and Dollhouse.
She was something of a sporadic regular in Buffy the Vampire Slayer, playing sometimes-evil slayer Faith Lehane in 20 episodes. She also played the same character in six episodes of Angel. Later, she went on to play Echo (also known as Caroline Farrell), the main character of Dollhouse.
And that's that! Undoubtably, there were other actors that appeared in multiple productions under Joss Whedon's directorship, but only as a byproduct of the fact that their characters crossed over into other shows or movies like Buffy and Angel. Those names include Sarah Michelle Gellar (Buffy Summers), Alyson Hannigan (Willow Rosenberg), James Marsters (Spike), David Boreanaz (Angel), Seth Green (Daniel "Oz" Osbourne), Julie Benz (Darla) and Juliet Landau (Drusilla). They weren't eligible for this list, as Whedon hadn't recycled them as different characters.